Yes. You can add photos and videos shared with you to Carousel Timeline from a conversation. If you add photos and videos to your Timeline, then it will automatically add them to your Dropbox account. To save photos to your Carousel, tap "Save Photo(s) to Dropbox" from within a conversation. If you want to keep just one photo, then tap the photo in full size and then tap "Save Photo to Dropbox" button located at the bottom on the screen. You can tap "View in My Timeline" button to see you saved photos in your Timeline.